WASHINGTON (Reuters) – Legislation allowing the construction of the Keystone oil pipeline from Canada to the U.S. Gulf of Mexico, repealing Obamacare and reducing the nation’s debt are at the top of Republicans’ 2015 agenda, House of Representatives Speaker John Boehner said on Thursday.

In his first news conference since Tuesday’s congressional elections that saw broad Republican victories, Boehner also said that if President Barack Obama unilaterally loosens some immigration regulations, he will “poison the well and there will be no chance of immigration reform moving” in the next two years.

Before the end of this year, Obama is expected to use his executive authority to help possibly millions of undocumented residents who have been living in the United States for an extended period, many raising families here. His actions could allow many of them to seek jobs in the United States without fear of deportation.

Obama held off taking such action earlier this year in the hope that Boehner’s Republicans would come together on a rewrite of U.S. immigration laws. In June 2013, the Senate passed a bipartisan bill.

But conservative opposition blocked Boehner and Obama has since pledged to go forward to help some of the nearly 12 million undocumented people.

Boehner also said he and Senator Mitch McConnell, who is scheduled to become Senate majority leader in January, will work in tandem to address the nearly $18 trillion U.S. debt. He did not elaborate.

While Boehner and McConnell have talked about breaking Washington’s political gridlock, the speaker on Thursday did not shy away from the prospect of sending Obama controversial bills that he likely would veto.

Those could include legislation requiring the Keystone pipeline that environmentalists oppose and repealing all or central features of Obama’s landmark healthcare law. (Reporting By David Lawder, Amanda Becker and Richard Cowan; Editing by Bill Trott)